The influence of CO2 and H2O on selective catalytic reduction of NO by NH3 over Cu/SAPO-34 catalyst
The influence of CO2 and H2O on selective catalytic reduction of NO by NH3 over Cu/SAPO-34 catalyst
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DOI：
10.1016/j.cej.2014.12.017
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发表时间：
2015-03
影响因子：
15.1
通讯作者：
Tie Yu;Jun Wang;Meiqing Shen;Jianqiang Wang;Wei Li
中科院分区：
文献类型：
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作者：
Tie Yu;Jun Wang;Meiqing Shen;Jianqiang Wang;Wei Li
在Cu/SAPO-34催化剂上确定了co2和H2O加成对NH3（NH3- scr）选择性催化还原NO的影响，并试图研究它们的影响。使用了两种Cu/SAPO-34样品，其Cu载荷相等，其酸度由SAPO-34载体中的Si量来调节。通过NH3-SCR、NH3-TPD、nh3氧化和动力学分析来评价co2和H2O的作用。NH3-SCR结果表明，在整个温度范围内，入口co2对NO转化的影响较小，而H2O的存在对NO转化有促进作用。NH3-TPD结果表明，H2O提高了Brønsted酸位的酸度和Cu2+的还原性，这两方面都有利于NH3-SCR活性的提高。此外，高温下H2O的存在抑制了nh3氧化过程中nh3的转化和副产物。通过对NH3-SCR和nh3在高温下氧化的动力学分析，估算了水蒸气存在时表观活化能（Ea）的变化，最后分别提出了不同温度范围内Cu/SAPO-34样品的酸度变化、Cu2+物种还原性变化与SCR机理之间的关系。
The effect of CO2and H2O addition on selective catalytic reduction of NO by NH3(NH3-SCR) over Cu/SAPO-34 catalysts was confirmed and we tried to study their influence in this research. Two Cu/SAPO-34 samples with the equivalent Cu loading were utilized, and their acidities were adjusted by the Si amounts in SAPO-34 supports. NH3-SCR, NH3-TPD, NH3oxidation and kinetic analysis were conducted to evaluate the role of CO2and H2O. NH3-SCR results revealed that CO2in the inlets presented less impact on NO conversion, while the presence of H2O enhanced NO conversion during the whole temperature range. NH3-TPD results showed H2O improved the acidity of Brønsted acid sites and the reducibility of Cu2+species, both of which benefited the NH3-SCR activity. In addition, the presence of H2O at high temperature inhibited NH3conversion and side-products during NH3oxidation process. Kinetic analysis of NH3-SCR and NH3oxidation at high temperature were further conducted to estimate the variation of apparent activation energy (Ea) for the presence of water vapor, and finally the relation between the variation of acidity, Cu2+species reducibility and the SCR mechanism over Cu/SAPO-34 sample at different temperature ranges was proposed, respectively.